The invention relates to photography and photographic equipment and more particularly relates to camera assemblies having a travel stop.
A variety of mechanisms are known for adjusting the focus of adjustable position camera lenses.
U.S. Pat. No. 3,220,308 teaches a camera lens that is focused manually by changing the airspace behind a front element. The front lens element is rotated relative to an axially movable, non-rotatable cam ring. Cams are provided on a collar that is joined to the front lens element. The collar and front element are rotated by the user to move the collar cams against an outer set of cams of the cam ring and vary the airspace. A separate, factory focus adjustment is provided for adjusting the infinity setting of the front airspace. The axial position of the cam ring is adjustable by rotating a focus adjustment ring against the nonrotatable, but axially movable cam ring. Cams are provided on the focus adjustment ring and bear against an inner set of cams of the cam ring. The cam ring focus can be adjusted by moving a gear sector that is joined to the cam ring. The gear sector is meshed with a tool having a pinon gear that is rotated by an axial shaft.
U.S. Pat. No. 5,613,168 is a similar to U.S. Pat. No. 3,220,308, but uses a Y-shaped special tool and of another tool in the form of a member that holds the focusing ring of the lens. Space must be available for those tools during the focus adjustment. In both U.S. Pat. No. 5,613,168 and U.S. Pat. No. 3,220,308, the adjusted lens element rotates relative to the camera body during use.
U.S. Pat. Nos. 4,910,544 and 4,764,783 disclose focus adjusting mechanisms for non-rotating lenses.
U.S. Pat. No. 4,764,783 teaches a lens focus adjusting mechanism in which different movable parts of a lens mechanism are adjusted relative to each other. U.S. Pat. No. 4,910,544 discloses a prior art camera, in which the position of an internal lens barrel support, relative to the camera body, is adjusted by the use of washers. The invention of this patent replaces the washers with an adjustable member.
The focus adjustment mechanisms described in the above patents all change all of the lens positions available during use.
It would thus be desirable to provide a camera assembly, in which factory lens adjustment does not require extensive access or complex tools.
It would also be desirable to provide a camera assembly, in which a lens in selectively movable between different positions along an optical axis, and the focus at one of those positions can be adjusted independent of the focus at another.
The invention is defined by the claims. The invention, in broader aspects, provides a camera assembly, which has a mount that defines an optical axis. A lens barrel has a main portion and a tracker protruding outwardly from the main portion. The lens barrel is movable along the optical axis between an extended position and a retracted position relative to the mount. The lens barrel is non-rotatable about the optical axis. A guide extends forward from the mount. A travel stop is mounted to the guide. The travel stop has a skid that is spirally sloped about the optical axis. The tracker defines a segment of the skid that is aligned with the tracker in a direction parallel to the optical axis and is contacted by the tracker in the extended position of the lens barrel. The segment can be shifted helically along the skid by pivoting the travel stop about the optical axis.
It is an advantageous effect of the invention that an improved camera assembly are provided, in which factory lens adjustment does not require extensive access or complex tools.
It is also an advantageous effect of the invention that an improved camera assembly are provided, in which a lens is selectively movable between different positions along an optical axis, and the focus at one of those positions can be adjusted independently of the focus at another of those positions.